How to use the fontbakery.utils.download_file function in fontbakery

from fontbakery.utils import download_file
  from fontTools.ttLib import TTFont
  from urllib.request import HTTPError
  LICENSE_DIRECTORY = {
    "OFL.txt": "ofl",
    "UFL.txt": "ufl",
    "LICENSE.txt": "apache"
  }
  filename = os.path.basename(ttFont.reader.file.name)
  fontname = filename.split('-')[0].lower()
  url = ("https://github.com/google/fonts/raw/master"
         "/{}/{}/{}").format(LICENSE_DIRECTORY[license],
                             fontname,
                             filename)
  try:
    fontfile = download_file(url)
    if fontfile:
      return TTFont(fontfile)
  except HTTPError:
    return None

from fontbakery.utils import download_file
  from fontTools.ttLib import TTFont
  from urllib.request import HTTPError
  LICENSE_DIRECTORY = {
    "OFL.txt": "ofl",
    "UFL.txt": "ufl",
    "LICENSE.txt": "apache"
  }
  filename = os.path.basename(ttFont.reader.file.name)
  fontname = filename.split('-')[0].lower()
  url = ("https://github.com/google/fonts/raw/master"
         "/{}/{}/{}").format(LICENSE_DIRECTORY[license],
                             fontname,
                             filename)
  try:
    fontfile = download_file(url)
    return TTFont(fontfile)
  except HTTPError:
    return None

git_ofl_prefix + 'belgrano/Belgrano-Regular.ttf',
        git_ofl_prefix + 'trirong/Trirong-Light.ttf',
        git_ofl_prefix + 'mitr/Mitr-Regular.ttf',
        git_ofl_prefix + 'overpass/Overpass-Regular.ttf',
        git_ofl_prefix + 'jura/Jura-Regular.ttf',
        git_ofl_prefix + 'overpass/Overpass-Black.ttf',
        git_ofl_prefix + 'montserrat/Montserrat-Regular.ttf',
        git_ofl_prefix + 'montserrat/Montserrat-Black.ttf',
        git_ofl_prefix + 'montserrat/Montserrat-Thin.ttf',
        git_apache_prefix + 'roboto/Roboto-Regular.ttf',
    ]

    fonts_data = []
    for font_url in fonts_urls:
        print('Downloading and generating glyph data for {}'.format(font_url))
        font_ttf = download_file(font_url)
        font = TTFont(font_ttf)
        fonts_data.append(get_font_glyph_data(font))

    print('Collating font data into glyph data file')
    glyph_data = collate_fonts_data(fonts_data)

    script_path = os.path.dirname(__file__)
    glyph_data_path = os.path.join(
        script_path, '..', 'Lib', 'fontbakery', 'desired_glyph_data.json'
    )

    print('Saving to {}'.format(glyph_data_path))
    with open(glyph_data_path, 'w') as glyph_file:
        json.dump(glyph_data, glyph_file, indent=4, cls=JsonSetEncoder)
    print('done')

git_ofl_prefix + 'belgrano/Belgrano-Regular.ttf',
        git_ofl_prefix + 'trirong/Trirong-Light.ttf',
        git_ofl_prefix + 'mitr/Mitr-Regular.ttf',
        git_ofl_prefix + 'overpass/Overpass-Regular.ttf',
        git_ofl_prefix + 'jura/Jura-Regular.ttf',
        git_ofl_prefix + 'overpass/Overpass-Black.ttf',
        git_ofl_prefix + 'montserrat/Montserrat-Regular.ttf',
        git_ofl_prefix + 'montserrat/Montserrat-Black.ttf',
        git_ofl_prefix + 'montserrat/Montserrat-Thin.ttf',
        git_apache_prefix + 'roboto/Roboto-Regular.ttf',
    ]

    fonts_data = []
    for font_url in fonts_urls:
        print(f'Downloading and generating glyph data for {font_url}')
        font_ttf = download_file(font_url)
        font = TTFont(font_ttf)
        fonts_data.append(get_font_glyph_data(font))

    print('Collating font data into glyph data file')
    glyph_data = collate_fonts_data(fonts_data)

    script_path = os.path.dirname(__file__)
    glyph_data_path = os.path.join(script_path, '..', 'desired_glyph_data.json')

    print(f'Saving to {glyph_data_path}')
    with open(glyph_data_path, 'w') as glyph_file:
        json.dump(glyph_data, glyph_file, indent=4, cls=JsonSetEncoder)
    print('done')

def download_family_from_Google_Fonts(family_name):
    """Return a zipfile containing a font family hosted on fonts.google.com"""
    from zipfile import ZipFile
    from fontbakery.utils import download_file
    url_prefix = 'https://fonts.google.com/download?family='
    url = '{}{}'.format(url_prefix, family_name.replace(' ', '+'))
    return ZipFile(download_file(url))

def download_family_from_Google_Fonts(familyname):
    """Return a zipfile containing a font family hosted on fonts.google.com"""
    from zipfile import ZipFile
    from fontbakery.utils import download_file
    url_prefix = 'https://fonts.google.com/download?family='
    url = '{}{}'.format(url_prefix, familyname.replace(' ', '+'))
    return ZipFile(download_file(url))